[Edaily Reporter Kim Seung-kwon ] There are two technologies in the medical device industry that are referred to as the “Holy Grail”: non-invasive blood glucose monitors that do not require blood sampling, and cuffless blood pressure monitors.

SkyLabs set its sights on the latter. Its flagship product is the ring-shaped blood pressure monitor, “CART BP pro.” Accuracy has always been the key challenge. CEO Lee Byung-hwan stated bluntly, “People only use a blood pressure monitor if it’s accurate,” adding, “Ultimately, countless latecomers have given up because they couldn’t prove its accuracy.”

AI, Not the Device, Reads Blood Pressure

The CART BP pro collects pulse wave signals using a photoplethysmography (PPG) sensor embedded in the ring. Blood pressure readings are calculated by the company’s proprietary AI deep learning algorithm. The device is designed without the algorithm embedded within it. CEO Lee explained, “It’s not a system where the algorithm is built into the device,” adding, “It’s not a structure that can be easily replicated just by having the device.”

Conventional 24-hour ambulatory blood pressure monitors (ABPMs) require a cuff to be wrapped around the arm, with pressure applied at regular intervals. This disrupts sleep and is burdensome to wear. The ring-type device alleviates these inconveniences. It is also used to detect nocturnal hypertension or masked hypertension, conditions that are easily missed during a single measurement in a clinic.

It is simple to use. Patients receive a prescription from a clinic or hospital and wear the ring for 24 hours. Measurement data is transmitted automatically. Healthcare providers make a diagnosis based on a report analyzing blood pressure patterns.

The barrier to access was lowered in June 2024 when the device became covered by national health insurance. At that time, Daewoong Pharmaceutical indicated that the insurance reimbursement rate per prescription would range from 15,000 to 18,000 won. Of this amount, the patient’s out-of-pocket cost was expected to be between 5,000 and 9,000 won. As of last August, the device had been used for more than 240,000 cumulative 24-hour ambulatory blood pressure measurements.

The market response was reflected in the numbers. According to the company, domestic prescriptions for 24-hour ambulatory blood pressure monitoring increased by 52.7% in the year following the launch of Cart BPI Pro. Cart BPI Pro holds a 52.4% market share of these prescriptions. In effect, the product has not only replaced the existing market but also created new demand. As of the end of July, the number of prescriptions over the past year exceeded 190,000.

It took a long time to prove its accuracy. CEO Lee said, “It took more than six years from development to clinical trials,” adding, “Even with the technology, it takes at least three to four years just to prove its efficacy through clinical trials.”

Since then, clinical evidence has been steadily accumulating. SkyLabs validated the algorithm’s accuracy against invasive arterial pressure measurements. It also compared the results to auscultatory blood pressure measurements conducted according to international standards. A study comparing the device with conventional ABPM in 40 hypertensive patients at Seoul National University Hospital was selected as an Editor’s Choice article in the Journal of the Korean Society of Cardiology. The study found that the device tracked diurnal blood pressure variations similarly to ABPM and met ESH criteria.

Additionally, the Cart BPI Pro passed four of the six key validation criteria for cuffless blood pressure monitors proposed by the European Society of Hypertension (ESH). These findings were presented at the Korean Society of Cardiology’s Spring Scientific Conference last April. Among the remaining criteria, the evaluation of blood pressure before and after taking antihypertensive medication is currently being conducted under the leadership of the Korean Society of Hypertension.

According to CEO Lee, Professor George Stergiou of Greece, who recently chaired a session at a European academic conference, described SkyLabs as “virtually the only company providing evidence in accordance with ESH validation criteria.” CEO Lee emphasized, “There have been various attempts both domestically and internationally, but they failed to achieve the required accuracy,” adding, “While there have been many claims, no company has yet proven its effectiveness.”

The academic community has also responded. The Korean Society of Hypertension has included cuffless blood pressure monitors in the “2026 Hypertension Clinical Practice Guidelines” for the first time. The recommendation is Grade IIb with Evidence Level B, indicating that their use may be considered for out-of-office blood pressure measurements.

On the other hand, there are also voices of caution. The society pointed out that cuffless blood pressure monitors also require verification of clinical accuracy. It also noted that there are still no internationally unified verification standards. Some medical institutions are delaying adoption due to measurement variability among patients.

CEO Lee explained, “To achieve a higher recommendation grade, outcome studies examining the impact on patient lifespan are necessary,” adding, “These studies take at least five years, typically more than 10, and are conducted as independent studies led by the Society.”

Expanding ‘Data Generation’ to Include Oxygen Saturation and the Five Major

Vital Signs
The next step is to expand the range of measured parameters. According to CEO Lee, the ring-type oxygen saturation monitor “CART O2” received approval in the first half of this year. He stated, “It will hit the market by November at the latest.” The technology is based on a system developed and approved during the COVID-19 pandemic.

Existing pulse oximeters require users to pinch or slip the device onto their fingertip. The pinching type can cause pain if worn for long periods, while the slip-on type—similar to a thimble—can easily slip off, interrupting measurements. CEO Lee noted, “Existing products have always had these drawbacks.” The ring-type device allows for continuous monitoring even while eating or washing one’s face. CART O2 is also a hospital-grade product covered by insurance.

A wrist-worn version, “CART VITAL,” is also in development. It is a product designed for hospital beds that measures five vital signs simultaneously. It also incorporates the features of CART O2. CEO Lee explained, “In response to requests from hospitals, we integrated the features we already had into a single product.” Equipped with a battery, display, and Wi-Fi, it is larger than the ring model. CEO Lee stated, “Our goal is to complete the approval process by the end of this year,” adding, “Actual market entry is expected around 2028.” The company anticipates no major obstacles, as the reimbursement rates will be based on existing categories.

The bedside monitoring market already includes products such as Daewoong Pharmaceutical’s “Think” and Vuno’s “DeepCAS.” SkyLabs distinguishes itself by emphasizing that its role differs from these competitors.

CEO Lee explained, “An in-hospital monitoring platform consists of a dashboard, EMR integration, and medical devices that collect data,” adding, “We are responsible for the medical devices that generate that data.” This means the company supplies data analyzed via deep learning in a format that hospitals can use—a key difference from existing devices, which simply pass along raw measurements. According to CEO Lee, the company’s product is the only cuffless blood pressure monitor available for hospital use worldwide. The company does not measure ECGs directly but integrates with third-party products.

The company views the smart ring craze as an opportunity, as wellness devices like Oura and the Galaxy Ring are popularizing the ring-shaped form factor. CEO Lee said, “Since the ECG feature was added to the Apple Watch, the market for arrhythmia diagnosis and treatment has actually grown,” adding, “Wellness products are effectively broadening public awareness.”